The present disclosure relates to injection molded solder systems. More particularly, the present disclosure relates to devices and methods for feeding solder to injection molded solder systems.
Injection molded solder (IMS) systems are described in U.S. Pat. Nos. 5,244,143, 5,971,058, and 6,231,333, all assigned to the assignee of the present invention, the content of each of which are incorporated herein by reference thereto. IMS systems are used for filling cavities in a graphite mold with molten solder that will be subsequently transferred and attached to a variety of electronic devices.
In general, IMS systems include a reservoir for molten solder, which is disposed over an injection plate or head. The injection plate is disposed over a graphite mold. The graphite mold when filled with solder, is in turn, disposed over a workpiece, such as a multi-layer ceramic substrate. The cavities in the graphite mold are aligned with the desired electrical contact locations on the substrate. To fill the graphite mold, molten solder is forced under gas pressure and/or drawn via vacuum from the reservoir through the injection head and into the mold cavities, which are later transferred to form electrical pathways on the substrate.
In order to properly form the desired electrical pathways, each cavity in the graphite mold is filled with molten solder during each molding cycle. In prior IMS systems, it has been necessary to interrupt the molding process between cycles to manually insert solder into the reservoir. For example, in molds having two thousand 20 mil holes the equivalent of a six inch length of 0.125 inches in diameter solder wire is required to fill the mold for each cycle.
However, it is desired to continuously operate IMS systems and, thus, it has been determined by the present application that a need exists for devices and methods that continuously and automatically feed solder to the reservoir of such IMS systems.